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Invasive species

Columbus, Metro Parks cut down more ash borer infected trees

As emerald ash borers spread, Metro Parks and the city pay to cut down many trees while saving a few

View SlideshowRequest to buy this photoAdam Cairns | DISPATCHDave Stickler prepares to cut down an ash tree along Dunedin Road in Clintonville. The Columbus employee’s work last week was part of the city’s $10 million program.

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A hike through Blacklick Woods Metro Park is a pleasant way for most people to enjoy a spring
day.

But a hike with the Metro Parks ecologist, Andrew Boose, reveals a decimated forest.

His mood turns somber as he walks past only a few of the thousands of leafless ash trees at
Blacklick, all of which were killed by emerald ash borers.

“Sad is one word for it,” Boose said, standing near a spot where healthy ash trees once provided
shade but were either cut down or fell. He estimated that 95 percent of the park’s mature ashes are
dead or dying. “If you’re the forest ecologist, you’re supposed to take care of it,
and (instead) you are watching it die in front of you,” Boose said. “It’s a hard pill to
swallow.

As the borer population grows exponentially, the rest of Franklin County soon will
look a lot like Blacklick. Except for a relatively few trees saved by injected pesticides, nearly
every mature ash tree in the county probably will be dead in four years.

“That’s my prediction,” said Dan Herms, an Ohio State University entomologist who
has studied the voracious green beetles since they were first detected in the United States, in
Michigan in 2002.

“It can take 10 years for 40 percent of the trees to die,” Herms said. “Then the
next 60 percent of the trees die in the next three to four years.”

The Asian beetles were an inadvertent import, infesting ash-wood packing crates
shipped from China to Detroit in the late 1990s. U.S. ash trees have no resistance to the insects,
which spread like wildfire across Michigan, Ohio and 16 other states. They’ve been in central Ohio
since 2003. State officials tried to eradicate the borers, but the effort quickly proved
futile.

These days, the Ohio Department of Agriculture tries to slow the borer’s spread by
advising people not to move infested firewood to uninfested areas. Ash borers have been detected in
64 of Ohio’s 88 counties.

Borer larvae kill ashes by tunneling through the soft wood under the bark, cutting
off the trees’ access to water and nutrients. The dead ash trees quickly dry out and become
brittle, making them a threat to fall on buildings, streets and people. That leaves city and parks
officials, especially those who have thousands of ashes on public land, with expensive
decisions.

Columbus is spending $10 million in a multiyear effort to remove most of an
estimated 30,000 ash trees and replace them with a different tree species, choosing among as many
as 50. Many of the ashes line streets in public rights of way.

Joe Sulak, the city forester, said $1.5 million will be spent this year on removing
trees. The money funds two full-time city crews that do nothing but cut down and chip ash trees,
and also four private companies hired to do the same thing.

“We’ve removed about 8,600 trees,” Sulak said.

Other cities preserve their trees. Chicago, according to news reports, will spend
$2 million to inject 35,000 ash trees with borer-killing pesticides.

Metro Parks spent $5,000 last year to inject 259 trees in its parks; many of
those provide shade for picnic areas.

Worthington has about 180 ash trees that have been treated with pesticides. Tom
Gilkey, Worthington’s maintenance supervisor, said a pesticide company offered to inject the trees
for free as an advertising tool to show homeowners that the treatments work.

The city is in the fourth year of a five-year agreement. Gilkey said he doesn’t
know if the city will spend the money to inject the trees once the deal expires. “It would probably
be cost- prohibitive to me,” he said.

Sulak said he’s optimistic that Columbus can keep up with the borers and cut trees
as they die.

Some residents have been unhappy that street trees are cut down when they still
have leaves. “We are removing trees that appear healthy, but they do have the insect,” Sulak
said.

Boose said he’s working to help his forest recover. That means keeping invasive
plants out of suddenly sunny parts of the forest so that new trees can grow and thrive.

He pointed to an oak seedling that had sprouted a few feet from the trunk of a
fallen ash. “That’s a good sign,” he said. “The forest will recover.”